1. Field of the Invention
This invention pertains generally to 3D printing, and more particularly to producing building materials for the construction industry.
2. Description of Related Art
Stereolithography and other rapid prototyping technologies are often used instead of conventional milling processes to prototype components, mechanical devices and tooling. Rapid prototyping processes are beginning to be used in industry to reduce the time and cost that is involved in creating models, mechanical devices, housings, prototypes or to produce small runs of finished products.
One rapid prototyping technology is additive layer manufacturing (ALM) that is also referred to as 3D printing. Unlike milling that removes material to produce an object, ALM builds a solid object from a series of layers of material with each layer printed and formed on top of the previous layer.
The ALM process begins with a computer aided design of an object and software that records a series of digital slices of the entire object. The pattern of each slice of the designed object is sent to the 3D printer to define the respective layers for construction by the printer. A thin layer of powder is spread out on a tray and the pattern of the first slice is applied to the layer of powder. ALM techniques generally use one of two different printing approaches: 1) laser or electron beams that cure or sinter material in each layer or 2) ejection of binder material from a nozzle head to create a patterned layer. The powder materials are fused together at the locations the laser or ejected material comes in contact with the surface of the powder.
Depending on the process that is used, many different types of materials can be used to form the patterned layers of the final product including, photopolymers, thermopolymers, plastics and metal powders.
Several commercial 3D-printing systems are currently available that accurately deposit a liquid binder onto the surface of the powder bed using a multiple array ink-jet printing head. These systems are based upon the work of Emanuel Sach at the Massachusetts Institute of Technology in the early 1990's.
Traditional 3D-printing technology is reserved for small-scale prototyping in a limited number of fields at a significant cost. Rapid prototyping machines generally produce objects that are not suitable as building materials or architectural parts because they have poor structural characteristics and durability. Accordingly, there is a need for powder compositions and methods for 3D-printing of architectural elements and construction materials that are strong, durable and easily configurable.